Rubberized broom fiber fabric



Patented Jan. 5, 1954 UNITED STATES ATENT rric RUBBERIZED BROOM FIBER FABRIC Henri Boinet and Ernest Boinet, Saint-Quentin, France No Drawing. Application May 10, 1951, Serial No. 225,676

3 Claims.

When it was attempted to replace the cotton duck or fabrics made from other fibres now used as structural material in the manufacture of rubberized articles such, for instance, as hose pipes, conveyor belts, etc. by fabrics made from hard fibres, such as the fibre of the common broom, hemp fibre, etc., it was found that the finished product were out comparatively easily and that it was not nearly as strong as the bare fabric.

It was ascertained that this drop in strength was ranging about 30 to 50%. Thus, not only was the whole advantage of using rot-proof fibres of great strength lost, but serious disadvantages arose, so that these attempts had to be abandoned.

The purpose of this invention is to overcome the above mentioned drawback and, in doing so, to permit the use of rot-proof hard fibres of great strength for the structural fabric of rubberized articles, without the strength of the finished product being very much less than that of the bare fabric.

With this object in view, the invention consists in a process of rubberizing broom fibre fabric comprising the step of subjecting said fabric, prior to the usual friction-calendering operations, to a pre-treatment for enabling said fibres to withstand said friction-calendering operations, that is to say, to enable them to undergo said operations without any too substantial deterioration in quality. The inventors have, indeed, discovered that the usual frictioncalendering operations applied to a hard fibre fabric damaged the fibres by making them brittle, just as cold-working makes metal wire brittle.

By protecting the fibres against this harmful efiect of the friction-calendering operations, the greater part of the initial strength of the fabric is retained, thus ensuring the benefit of the great strength of the hard fibres used.

This protective pre-treatment of the fibres can advantageously comprise coating, or even, impregnating the fibres with some suitable substance, preferably a rubber mixture, if possible vulcanizable.

The invention has also for its object, as novel industrial products, articles made of rubberized fabric of which the structural material is a hard fibre fabric, such as, for instance, a fabric made from fibre of the common broom, processed as stated above, that is to say, the fibres of which have been coated, for instance, impregnated, with a vulcanizable rubber mixture, such coating or impregnation being quite distinct from that formed by the friction-calendering operations.

Merely as an example, but without in any way 2 limiting the scope of the invention, the followmg 1s a description of one particular method of obtaining a rubberized fabric, according to the invention.

First of all, in order to reduce the humidity content of the hard fibre fabric such as a fabric made from broom fibre, the fabric to be used as structural material for a reinforced rubber article is subjected to a pre-drying process. The fabric is given a maximum soaking in a dissolved vulcanizable rubber mixture. This impregnation can be made in any suitable manner, for 1nstance, on a rubberizing machine, by pulverization, etc. When the impregnation. has been finished, the fabric is thoroughly dried at a temperature lower than that of rubber vulcanization and which the fibres can withstand without deterioration.

The protective pie-processing is then terminated, and the fabric thus prepared can be subjected to the usual friction-calendering operations without the strength of the finished reinforced rubber article having been substantially reduced as compared with the strength of the original fabric.

The desired articles are then manufactured by the usual methods as in the case of cotton structural material.

It goes without saying that the invention is in no way limited to the details of embodiment stated above, as these have been given merely by way of information.

Having thus described the invention what we claim is:

l. A fabric of broom fibres having a sub coating of a rubber solution rendering said broom fibers pliable and reinforced by an outer coating of calendered vulcanized rubber.

2. A conveyer belt consisting of a fabric of broom fibers having a sub-coating of a rubber solution rendering said broom fibers pliable and reinforced by an outer coating of calendered vulcanized rubber.

3. A hose pipe consisting of a fabric of broom fibers having a sub-coating of a rubber solution rendering said broom fibers pliable and reinforced by an outer coating of calendered vulcanized rubber.

HENRI BOINET. ERNEST BOINET.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 247,836 Mayall Oct. l, 1881 354,993 Torrey Dec. 28, 1886 837,193 Candcnberg Nov. 27, 1906 

1. A FABRIC OF BROOM FIBRES HAVING A SUBCOATING OF A RUBBER SOLUTION RENDERING SAID BROOM FIBERS PLIABLE AND REINFORCED BY AN OUTER COATING OF CALENDERED VULCANIZED RUBBER. 